Phosphine-Mediated <i>de Novo</i> Arylamidation of α-Allylic Allenoates and Isocyanates via Bicyclo[3.1.0]hexene Access to Aryl Amides

Amides are highly valuable structural units in pharmaceuticals and organic materials. Despite enormous progress in this field, <i>de novo</i> construction of aryl amides is underdeveloped. Here we present a phosphine-mediated arylamidine of α-allylic-substituted allenoates with isocyanates. This methodology features broad substrate scope, simple experimental operation, high efficiency, and good functional group tolerance. Isolation experiments on bicyclo[3.1.0]hexene, coupled with deuterium experiments, clarify a stepwise pathway involving ring-opening and aromatization processes, with the ring-opening step identified as crucial for achieving the aryl amides. The synthetic utility of this protocol has been further demonstrated by carrying out several downstream transformations and a concise formal synthesis of the benzene-1,3,5-tricarboxamide (BTA) molecule.